Homogeneous Catalysis of Hydrogen Isotope Exchange Between D2 and Ethanol by Chlorotris(triphenyIphosphine)rhodium(I). II. In Chloroform-Ethanol

1974 ◽  
Vol 52 (12) ◽  
pp. 2226-2235 ◽  
Author(s):  
Graeme Strathdee ◽  
Russell Given
Keyword(s):  
Activation Energy ◽  
Computer Simulation ◽  
Exchange Reaction ◽  
Homogeneous Catalysis ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Side Reaction ◽  
Rate Determining Step ◽  
Inverse Isotope Effect

The kinetics and mechanism of D2 exchange catalyzed by RhCl(PPh3)3 have been studied in chloroform–ethanol solutions. Interpretation of the results was complicated by a side reaction of the solvent to yield HCl, RhHCl2(PPh3)2, C2H5Cl, CH2Cl2, Ph3PO, and other phosphorus(V) species. Computer simulation of the exchange reaction was used to show that the observed inverse isotope effect [Formula: see text] could arise only if the rate determining step was the activation of D2, HD, and H2 by RhCl(PPh3)3.The D2 exchange reaction rate was extremely dependent on solvent composition and decreased 30 times between 6 and 96 mol% C2H5OH. The activation energy for D2 exchange was 101 ± 9 kJ mol−1 at 58 mol% C2H5OH, and 86 ± 8 kJ mol−1 at 6 mol% C2H5OH. These data suggested that solvent–catalyst bonding interactions were important.

Hydrogen isotope exchange between D2 and H2O catalyzed by platinum plate

1989 ◽  
Vol 67 (5) ◽  
pp. 857-861 ◽  
Author(s):  
Shin-Ichi Miyamoto ◽  
Tetsuo Sakka ◽  
Matae Iwasaki
Keyword(s):  
Kinetic Model ◽  
Exchange Reaction ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Hydrogen Adsorption ◽  
Platinum Catalyst ◽  
Isotope Exchange Reaction ◽  
Hydrogen Isotope Exchange ◽  
Supported Platinum

The reaction rate of hydrogen isotope exchange between D2 and H2O catalyzed by platinum plate is studied. The exchange reaction is described with the kinetic model which is the modification of that for the exchange reaction catalyzed by alumina-supported platinum catalyst. For the comparison of experimental results with this model relative amount of the number of sites for hydrogen adsorption was estimated from the initial rate of hydrogen isotope exchange between H2 and D2 on the same surface. The results show that the kinetic model is applicable for the plate catalyst if the number of the sites for hydrogen absorption, which is very sensitive to the surface state of the catalyst, was estimated not from the macroscopic surface area but from our scheme. Keywords: hydrogen isotope exchange reaction, platinum plate as catalyst.

Homogeneous Catalysis of Hydrogen Isotope Exchange between D2 and Ethanol by Chlorotris(triphenylphosphine)rhodium(I). I. in Benzene–Ethanol

1974 ◽  
Vol 52 (12) ◽  
pp. 2216-2225 ◽  
Author(s):  
Graeme Strathdee ◽  
Russell Given
Keyword(s):  
Activation Energy ◽  
Isotope Effect ◽  
Homogeneous Catalysis ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Mixed Solvent ◽  
Product Distribution ◽  
Volume Percent ◽  
Relative Stabilities ◽  
Rate Of Activation

The kinetics and mechanism of D2–C2H5OH exchange catalyzed by chlorotris(triphenylphosphine)rhodium(I) have been studied in 50 volume percent benzene-ethanol. In this mixed solvent, the rate of exchange was low and was limited by the rate of transfer of deuterium from dideuteridochlorotris(triphenylphosphine)rhodium(III) to the solvent, and not by the rate of activation of D2. The activation energy for the overall process was relatively low, 35 kJ mol−1. In addition, new data have been presented for the catalysis of H2–D2 exchange in benzene by RhCl(PPh3)3. Analysis of the apparent HD:D2 isotope effect that is observed during D2–C2–H5OH exchange suggests that this effect originates with the relative stabilities of the D2, HD, and H2 adducts with RhCl(PPh3)3, or by control of the HD and H2 product distribution by the H2–D2 equilibration reaction.

Homogeneous Catalysis of Hydrogen Isotope Exchange between D2 and Ethanol by Dichlorotris(triphenylphosphine) Ruthenium(II)

1975 ◽  
Vol 53 (10) ◽  
pp. 1402-1409 ◽  
Author(s):  
Graeme Strathdee ◽  
Russell Given
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Homogeneous Catalysis ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Homogeneous Catalyst ◽  
Hydrogen Isotope Exchange ◽  
Temperature Range

Rates of D2–ethanol exchange catalyzed by solutions of dichlorotris(triphenylphosphine) ruthenium(II) in 1:1 benzene–ethanol are reported as a function of the concentrations of ruthenium, deuterium, triphenylphosphine, and HCl. The rates were extremely fast, and approached 10−3 mol D2 l−1 s−1 at 333 K with 1.3 mmol/l Ru. Over the temperature range 263 to 303 K, the apparent activation energy was 85 kJ/mol. The kinetics have been interpreted in terms of a mechanism in which activation of D2 by RuCl2L3 is rate-controlling. A comparison is made between the characteristics of this homogeneous catalyst and those of the related RhClL3.

scholarly journals Are rate and selectivity correlated in iridium-catalysed hydrogen isotope exchange reactions?

2021 ◽  
Author(s):  
Daria S. Timofeeva ◽  
David M Lindsay ◽  
W. J. Kerr ◽  
David James Nelson
Keyword(s):  
Functional Groups ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Exchange Reactions ◽  
Reaction Selectivity ◽  
Hydrogen Isotope Exchange ◽  
The Relationship

Herein we examine the relationship between reaction rate and reaction selectivity in iridium-catalysed hydrogen isotope exchange (HIE) reactions directed by Lewis basic functional groups. We have recently develped a directing...

Isotope exchange reactions of the hydrogen H-5 of selected pyrimidine derivatives and the preparation of tritium-labeled pyrimidines

2011 ◽  
Vol 76 (12) ◽  
pp. 1567-1577 ◽  
Author(s):  
Martin Dračínský ◽  
Petr Jansa ◽  
Tomáš Elbert
Keyword(s):  
Exchange Reaction ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Tritiated Water ◽  
Solvent Composition ◽  
Exchange Reactions ◽  
Pyrimidine Derivatives ◽  
Isotope Exchange Reaction ◽  
Nmr Techniques ◽  
Tracer Experiments

The hydrogen-to-deuterium isotope exchange reaction of hydrogen in position 5 of pyrimidine derivatives was studied using NMR techniques. The dependence of the reaction rate on the pH and on the solvent composition was explored. In tracer experiments using tritiated water, the application of this exchange reaction was tested for the preparation of pyrimidine derivatives labeled by tritium.

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